Quick answer: Unity ParticleSystem with the Trails module enabled but no visible trail? Default trail lifetime is 0 or trail width is 0 — both must be positive.

A rocket emitter shoots particles cleanly but the configured trails don’t appear. The Trails module is on but its lifetime / width are zero.

Trail Lifetime > 0

Trail Lifetime defaults vary per template. A value of 0 means no trail — the streak length is zero. Set 0.5-2.0s for visible trails.

Width Over Trail

The Width Over Trail curve controls the trail’s thickness from particle to end. Default 1.0 gives constant width. Tapering to 0 at the end softens.

Trail Material

Renderer module → Trail Material. Without a material, the trail uses the particle’s material — may not be designed for trail rendering. Use Sprites/Default + an additive shader for hot trails.

Texture Mode

Stretch the texture along the trail or repeat it. Stretch reads cleanly for streaks; repeat for dashed lines.

Verifying

Particles emit visible trails behind them. Width and color cycle as authored.

“Trails need lifetime, width, and material. All three; missing any = invisible.”

Build VFX from a template scene that already has working trails — faster than auditing the Trails module fields each time.